For a professional, more important than a raise (they wont admit obviously) is the resources/tools to make a good work. Invest in things that will make them more productive, find the chores and try to minimize them. Exemple of chores that would make people happy if removed/reduced:
1) long chain of approvals for simple requests
2) slow computers
3) too hot or too cold rooms
4) outside noise
5) printers not working / replacement of tonner taking too long
etc
In short everything that is not really important should not take time or interfere with what is important, so one of the more important jobs of a HoD is to remove the stones in the path of who is working.